1. Field of the Invention
The present invention relates to methods for increasing the generation of positive transformants of a filamentous fungal host cell expressing multiple recombinant polypeptides.
2. Description of the Related Art
Recombinant production of a polypeptide in a filamentous fungal host cell may provide for a more desirable vehicle for producing the polypeptide in commercially relevant quantities. The recombinant production of a polypeptide is generally accomplished by constructing an expression cassette in which the DNA coding for the polypeptide is placed under the expression control of a promoter from a regulated gene. The expression cassette is introduced into the host cell, usually by plasmid-mediated transformation. Production of the polypeptide is then achieved by culturing the transformed host cell under inducing conditions necessary for the proper functioning of the promoter contained on the expression cassette.
Filamentous fungal cells may be transformed with a vector by a process involving protoplast formation, transformation of the protoplasts, and regeneration of the cell wall in a manner known per se. Co-transformation of two or more vectors expressing multiple recombinant proteins does not efficiently provide positive transformants producing significant amounts of the multiple recombinant polypeptides.
There is a need in the art for methods that improve the efficiency of obtaining positive transformants producing significant amounts of multiple recombinant polypeptides to reduce the number of transformants to be screened compared to positive transformants generated by co-transformation of vectors for each of the multiple recombinant polypeptides.
The present invention provides improved methods for the generation of positive transformants of a filamentous fungal host cell expressing multiple recombinant polypeptides.